it was found that this conventional WWT system has no significant size-selectivity for particle removal based on SEM analysis of aliquots drawn from various points throughout the system. Additionally, nanoparticles were observed immediately prior to the point of discharge to municipal wastewater, indicating a high probability that these materials enter the municipal wastewater stream. As characterization of nanoparticles becomes more difficult with increasing matrix complexity , and that nanomaterials may adversely affect biota in publically owned treatmentworks, it is important to study the contents of wastewater before it is discharged to the municipal waste stream.